This invention relates to an apparatus and method for jetting a fluid. More particularly, but not by way of limitation, this invention relates to an apparatus and method for jetting a fluid into a container such as a tubular member in order to chemically treat and/or wash the tubular member.
In the oil and gas industry, tubular members are utilized to deliver hydrocarbons and water in a variety of different settings. For instance, an oil and gas well bore may be drilled to a subterranean reservoir. The tubular member is placed in the well bore and can be used as a conduit to produce oil, gas and water. As another example, pipelines are utilized in order to deliver produced hydrocarbons from one site to another site.
As those of ordinary skill in the art will recognize, these tubular members are susceptible to corrosion and deposition of materials such as scale. Operators find it necessary to attempt to prevent these problems, or alternatively, in those cases were it has already occurred, to attempt to clean the tubular member.
In the prior art, various devices have been attempted to treat and/or wash tubular members. These include casing scrapers that comprise a pad mounted on a cylindrical body, with the pad designed to scrape the tubular walls. Additionally, the prior art has developed a devicexe2x80x94known as a pig that is essentially a spherical member with scrapers thereon. The pig is inserted into tubular member and pumped from a first location to a second location in an attempt to clean the inner diameter of the tubular member. However, all these prior art devices lack the ability to adequate circulate a treating chemical and/or clean the walls of the tubular string.
Therefore, there is a need for an apparatus and method that will adequately jet, circulate, and recirculate treating fluids at the desired point of treatment in the well bore. There is also a need for an apparatus and method that will remove scale and other depositions of materials on walls of tubular members. These and other needs will be met by the present invention as will be apparent from a reading of the description of the invention.
An apparatus for jetting a fluid within a tubular string is disclosed. The apparatus may comprise a cylindrical member having an outer portion and an inner portion, an outer sleeve disposed about the cylindrical member forming an annulus area, and a venturi means for jetting the fluid against the inner diameter walls of the tubular string.
In the preferred embodiment, the venturi means comprises a nozzle disposed within the cylindrical member and a throat formed within the outer sleeve, and wherein the throat is aligned with the nozzle. Also included in the preferred embodiment is a recirculation port formed on the outer sleeve for communicating the fluid from a second annulus area to a first annulus area adjacent the throat.
In one embodiment, the venturi means contains a plurality of nozzles and throats, with the nozzles being configured within the cylindrical member and throats being configured on the outer sleeve. In another embodiment, the plurality of nozzles are oriented at an offset angle relative to the center axis of the cylindrical member. Additionally, the plurality of passageways forming the plurality of throats are oriented at an angle corresponding to the plurality of nozzles.
In another embodiment, some of the plurality of nozzles face radially outward toward the tubular string""s inner diameter wall and at least one nozzle is rotated 90 degrees downward to project longitudinally downward relative to the center axis of the cylindrical member.
In one of the disclosed embodiments, the cylindrical member is connected to a drill string concentrically placed within the tubular string. In yet another embodiment, the cylindrical member is connected to a coiled tubing string concentrically placed within the tubular string.
Also disclosed is a method of cleaning a tubular string with a power medium. The method includes providing a wash apparatus concentrically positioned within the tubular string. The wash apparatus comprises a cylindrical member, a nozzle formed within the cylindrical member, an outer sleeve disposed about the cylindrical member forming a first and second annulus area, a throat formed on the outer sleeve, with the throat being aligned with the nozzle, and, a recirculation passage located on the outer sleeve. The power medium may be a fluid or air. In the preferred embodiment, the power medium is a fluid.
The method further comprises circulating the power medium down the inner portion of the cylindrical member and exiting the power medium from the nozzle. An area of low pressure is formed at the tip of the nozzle within the first annulus area which causes fluid from the second annulus to enter the first annulus via the recirculation passage and thereafter mixing the power medium and fluid within the throat. Thereafter, the mixture is exited from the throat.
In the preferred embodiment, the cylindrical member contains a plurality of nozzles, and the outer sleeve contains a plurality of corresponding throats. With this embodiment, the method further includes exiting the fluid from the plurality of nozzles. An area of low pressure is formed within the first annulus area and fluid within the second annulus area is drawn into the first annulus area. Thereafter, the power medium and fluid enters the throat and is mixed therein. Next, the fluid is exited from the plurality of throats.
In one of the embodiments disclosed, the plurality of nozzles and the plurality of throats are oriented at an off set angle relative to the center of axis of the cylindrical member. With this embodiment, the method includes exiting the fluid in a swirling pattern from the plurality of corresponding throats.
In yet another embodiment, at least one of the plurality of nozzles faces radially outward toward the tubular string""s inner diameter walls and wherein at least one of the plurality of nozzles is rotated 90 degrees to project longitudinally downward relative to the center of axis of the cylindrical member. With this embodiment, the method includes exiting the fluid from the plurality of radially projecting throats thereby striking the inner diameter wall of the tubular string. Also included with this embodiment is that the fluid will exit from the downwardly projected throats relative to the center of axis of said cylindrical member.
In still another embodiment, the operator may find it desirable to chemically treat the tubular member. The purpose for treating may be corrosion control, scale removal, etc. Thus, the method would include pumping a chemical down the inner portion of the cylindrical member. The chemical slurry being pumped down becomes in effect the power medium. The chemical is then jetted, according to the teachings of the present invention, into the walls of the tubular member and into the second annulus area. The treating chemical may be selected from the group consisting of solvents for paraffin and scale removal, acid compounds for subterranean reservoirs, or chelate agents.
An advantage of the present invention includes the venturi means allowing for high pressure energy transfer between the power medium and the fluid that is in place in the annulus. Another advantage is that the novel device and method allow for a recirculation pattern of fluid within the annulus.
Still yet another advantage is that the power medium being pumped down hole may be a fluid composition that contains chemicals for treating the tubular member and/or perforations. Yet another advantage is that the device and method may be used to treat down hole well bores, surface pipe lines, flow lines, etc. It is also possible to wash perforations contained within the tubular member in the case of a subterranean well.
A feature of the present invention includes use of a venturi device for jetting and recirculating fluid contained within the annulus of the tubular member. Another feature is that the apparatus of the present invention may be run on work strings including drill strings, production strings and/or coiled tubing strings. Yet another feature includes having a plurality of nozzles operatively associated with a plurality of throats on the device.
Still yet another feature is that the apparatus includes an inner cylindrical member concentrically disposed within a sleeve. Another feature includes venturi jets that point radially outward as well as longitudinally downward from the bottom face of the apparatus. Yet another feature is that in a second embodiment, the nozzles and throats may be inclined at an offset angle so that a swirling action may be imparted to the fluid in the annulus.